高分请教,日历的算法!!!!

 1'获取正确的日期   
 2Function YmdList(yi,mi,di)   
 3Dim y,m,d   
 4'年   
 5if yi="" or isnumeric(yi)=false then   
 6y=year(now())   
 7else   
 8y=yi   
 9end if   
10  
11'月   
12if mi="" or isnumeric(mi)=false then   
13m=Month(now())   
14else   
15m=mi   
16end if   
17if m>13 then m=13   
18if m<1 then m=1   
19  
20'日   
21if di="" or isnumeric(di)=false then   
22d=day(now())   
23else   
24d=di   
25end if   
26if m=2 and d>28 then   
27if y mod 4=0 then   
28if y mod 100=0 then   
29if y mod 1000=0 then   
30d=29   
31else   
32d=28   
33end if   
34else   
35d=29   
36end if   
37else   
38d=28   
39end if   
40end if   
41if (m=4 or m=6 or m=9 or m=11) and d>30 then d=30   
42if d<1 then d=1   
43YmdList=cstr(y)&"-"&cstr(m)&"-"&cstr(d)   
44End Function   

 1'获取正确的日期时间   
 2Function YmdHms(yi,mi,di,hi,msi,si)   
 3dim h,ms,s   
 4  
 5'时   
 6if hi="" or isnumeric(hi)=false then   
 7h=0   
 8else   
 9h=hi   
10end if   
11if h<0 then h=0   
12if h>=24 then h=23   
13  
14'分   
15if msi="" or isnumeric(msi)=false then   
16ms=0   
17else   
18ms=msi   
19end if   
20if ms<0 then ms=0   
21if ms>=60 then ms=59   
22  
23'秒   
24if si="" or isnumeric(si)=false then   
25s=0   
26else   
27s=si   
28end if   
29if s<0 then s=0   
30if s>=60 then s=59   
31YmdHms=YmdList(yi,mi,di)&" "&h&":"&ms&":"&s   
32End Function

 1'每月的天数   
 2Function MonthDays(Yeari,Monthi)   
 3Dim Days   
 4Days=0   
 5if Monthi=2 then   
 6if Yeari mod 4=0 then   
 7if Yeari mod 100=0 then   
 8if Yeari mod 1000=0 then   
 9Days=29   
10else   
11Days=28   
12end if   
13else   
14Days=29   
15end if   
16else   
17Days=28   
18end if   
19else   
20if Monthi=4 or Monthi=6 or Monthi=9 or Monthi=11 then   
21Days=30   
22else   
23Days=31   
24end if   
25end if   
26MonthDays=Days   
27End Function

 1'每天是星期几   
 2Function DayWeek(Yeari,Monthi,Dayi)   
 3Dim Days   
 4Days=0   
 5Dim yi,mi   
 6'年   
 7For yi=2001 to Yeari-1   
 8if yi mod 4=0 then   
 9if yi mod 100=0 then   
10if yi mod 1000=0 then   
11Days=Days+366   
12else   
13Days=Days+365   
14end if   
15else   
16Days=Days+366   
17end if   
18else   
19Days=Days+365   
20end if   
21Next   
22'月   
23For mi=1 to Monthi-1   
24Days=Days+MonthDays(Yeari,mi)   
25Next   
26Days=Days+Dayi   
27DayWeek=Days mod 7   
28End Function

 1'星期的中文表示方法   
 2Function WeekName(wi)   
 3Select case wi   
 4case 0   
 5WeekName="日"   
 6case 1   
 7WeekName="一"   
 8case 2   
 9WeekName="二"   
10case 3   
11WeekName="三"   
12case 4   
13WeekName="四"   
14case 5   
15WeekName="五"   
16case 6   
17WeekName="六"   
18End Select   
19WeekName="星期"&WeekName   
20End Function   
21  
22  
23function FirstDayOfWeek (nYear, nIndex)   
24dim dt, n   
25dt = dateserial(nYear, 1,1)   
26n = weekday(dt)   
27if n > 2 then   
28dt = dateadd("d", 7-n+2 , dt)   
29else   
30dt = dateadd("d", 2-n , dt)   
31end if   
32  
33if nIndex > 1 then   
34dt = dateadd("d", 7*(nIndex-1) , dt)   
35end if   
36FirstDayOfWeek = dt   
37end function